This invention relates generally to electromagnetic relays and more specifically to flat electromagnetic relays which have a very small width when vertically oriented and or a very small height when horizontally oriented.
Flat electromagnetic relays are already known from U.S. Pat. No. 4,010,433 granted to Hiromi Nishimura et al Mar. 1, 1977; U.S. Pat. No. 4,031,493 granted to Michael Van Der Wielen Jun. 21, 1977; U.S. Pat. No. 4,272,745 to Takashi Tanaka Jun. 9, 1981: U.S. Pat. No. 4,290,037 granted to Takashi Inagawa et al Sep. 15, 1981; U.S. Pat. No. 4,517,537 granted to Josef Weiser et al May 14, 1985 and from U.S. Pat. No. 4,684,909 granted to Michael Dittmann Aug. 4, 1987.
A flat electromagnetic relay is also already known from U.S. Pat. No. 5,038,123 granted to Christopher Alan Brandon Aug. 6, 1991. This patent which is incorporated herein by reference discloses a flat electromagnetic relay comprising a lead assembly having six stamped insert molded circuit leads, an armature frame pivotally supporting a balanced beam armature which carries two contact bars, a coil assembly and an electromagnetic frame having two diagonally arranged pole wings which are on opposite sides and ends of the armature. The armature is biased into a first operative position where the contact bar at one shunts two circuit leads. When the coil is energized, the armature is pivoted into a second operative position where the contact bar at the other end shunts two other circuit leads.
While this flat electromagnetic relay has many advantages, it has a disadvantage in that the male terminal blades of the six circuit leads are symmetrically arranged while the electric circuitry is not. Thus in the absence of orientation structure, the relay can be turned 180 degrees and plugged in backwards resulting in an operating dysfunction because the terminal blades for the normally open circuit leads are in the position of the terminal blades for the normally closed circuit leads and vice versa.